The Cloning And Disease Resistance Analysis Of Monoubiquitination E3Ligase From Oryza Sativa L.

The rice diseases result in big loss in the yield and quality seriously every year. It is found that the gene AtHUB1(Arabidopsis thaliana Histone Monoubiquitination1), encoding a E3ligase, is related to the regulation of flowering and disease denfense response in Arabidopsis. The homolog of HUB1in rice, OsHUB1, was cloned and its function was studied.By RT-PCR, OsHUBl was amplified from rice. The sequencing showed that its ORF has2665bp and encodes885amino acids. The C-terminal of the OsHUB1has a RING finger domain which has a high degree of homology with other E3ligase from different plants.The expression patterns of OsHUB1under different conditions were checked to illuminate the relationship between OsHUB1gene and disease defense responses. The results showed that the expression of OsHUBl in rice can be induced in2d after inoculation with Rhizoctonia solani and decreased in3h after inoculation with Xanthomonas oryzae pv. Oryzae. It is concluded that OsHUB1can response to rice sheath blight and Rice bacterial leaf blight in different way. On the other hand, both of SA and JA can induced the expression of OsHUB1in6h. It indicated that OsHUB1involved in disease resistance by SA-and JA-mediated signaling pathway.In order to analyze the biological function of OsHUB1, we generated the overexpression of OsHUB1in Arabidopsis HUB1deficient mutant hubl mutant is flowering early and more sensitive to necrotrophic pathogenic fungi. The overexpression lines of OsHUB1in hub1showed normal flowering and had the same disease resistance phynotype to necrotrophic pathogenic fungi Alternaria brassicicola with wild type. These data demonstrated that OsHUB1and AtHUBl had similar function at least in the regulation of flowering and resistance to necrotrophic pathogenic fungi Alternaria brassicicola.To study the function of OsHUB1in rice further, the recombinant plasmid pTCK303-OsHUB1was constructed for RNAi assay.32rice RNAi mutants (T1) of OsHUB1gene were already generated by agriculture-mediated transformation. These mutants will be very helpful to explain the function of OsHUB1in rice.